This invention relates to an endless track assembly for supporting an implement or vehicle, such as, for example, of the general type disclosed in U.S. Pat. Nos. 7,380,892, 7,726,749 and 9,440,691. In such a track assembly, it is desirable for the track assembly to accommodate uneven loading across the track assembly wheels, including the end wheels for the endless track or belt and the smaller bogie wheels which engage the bottom or lower run of the endless track or belt. It is also desirable to provide more uniform ground contact over uneven terrain in order to minimize stresses and vibrations in both the track assembly components and in the implement or vehicle supported by the track assembly. The decrease in stresses and vibration in an implement being supported by the track assembly also reduces any discomfort to the driver of a tractor or vehicle that is pulling the implement supported by the endless track assembly.